title: Low potential detection of glutamate based on the electrocatalytic oxidation of NADH at thionine/single-walled carbon nanotubes composite modified electrode.
abstract: A glutamate biosensor based on the electrocatalytic oxidation of reduced nicotinamide adenine dinucleotide (NADH), which was generated by the enzymatic reaction, was developed via employing a single-walled carbon nanotubes/thionine (Th-SWNTs) nanocomposite as a mediator and an enzyme immobilization matrix. The biosensor, which was fabricated by immobilizing glutamate dehydrogenase (GlDH) on the surface of Th-SWNTs, exhibited a rapid response (ca. 5s), a low detection limit (0.1 microM), a wide and useful linear range (0.5-400 microM), high sensitivity (137.3+/-15.7) microA mM(-1)cm(-2), higher biological affinity, as well as good stability and repeatability. In addition, the common interfering species, such as ascorbic acid, uric acid, and 4-acetamidophenol, did not cause any interference due to the use of a low operating potential (190 mV vs. NHE). The biosensor can be used to quantify the concentration of glutamate in the physiological level. The Th-SWNTs system represents a simple and effective approach to the integration of dehydrogenase and electrodes, which can provide analytical access to a large group of enzymes for wide range of bioelectrochemical applications including biosensors and biofuel cells.
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Meng
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Chen
authors.forename: Chenxin
authors.initials: C
authors.lastname: Cai
authors.forename: Yongming
authors.initials: Y
authors.lastname: Sun
authors.forename: Zhenhong
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002384:Catalysis; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D018698:Glutamic Acid / Q000737:chemistry*; D008839:Microelectrodes; D009243:NAD / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010640:Phenothiazines / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D037742:Nanotubes, Carbon; D010640:Phenothiazines; D009243:NAD; D018698:Glutamic Acid; C009469:thionine